[Terrapreta] volatile matter and char
Gerald Van Koeverden
vnkvrdn at yahoo.ca
Fri Dec 21 18:32:58 CST 2007
None of our discussions seem to have got us any closer to what "VM"
is....
1. To what extent is VM just a concentration of pre-existing organic
compounds in wood? For example, the tree has produced certain
chemicals to protect its trunk from insect/diisease; are these just
becoming more concentrated?
2. To what extent is VM new toxic chemicals produced through the
heat of pyrolysis? At what temperature are these produced? If
higher temperatures are their origin, then it might well be that
lesser/lower carbonized/torrified wood (the stage of cell collapse
and dehydration), such as suggested by Nikolaus, might be the
healthiest precursor to fertile 'char'. It could be that only the
intermediate 'incomplete' carbonizing stages produce a toxic charcoal.
Until we get a better handle on this VM mystery substance - its true
nature, origin and decomposition - we just keep going round in circles.
Gerrit
On 21-Dec-07, at 12:54 PM, Edward Someus wrote:
> Antal makes more gasification with high burn off, resulting more
> alkaline ash. This is not reduce VM much but increases ash
> significantly, we do not want.
>
> True carbonization is in absence of any air, process is made in
> vacuum and it gas out not gasify.
>
> Sincerely yours: Edward Someus (environmental engineer)
> Terra Humana Clean Tech Ltd. (ISO 9001/ISO 14001)
> 3R Environmental Technologies Ltd.
> ADDRESS: H-1222 Budapest, Szechenyi 59, Hungary
> TEL handy: +(36-20) 201 7557
> TEL / FAX: +(36-1) 424 0224
> TEL SKYPE phone via computer: Edward Someus
> 3R TERRACARBON: http://www.terrenum.net
> 3R CLEANCOAL ENERGY: http://www.nvirocleantech.com
>
> -------Original Message-------
>
> From: Gerald Van Koeverden
> Date: 2007.12.21. 14:02:58
> To: Edward Someus
> Subject: Re: [Terrapreta] volatile matter and char
>
> Edward,
>
> I understand that VM is not composed of naturally occurring
> substances, but that it itself is a product of the carbonizing
> process.
>
> If this is so, then maybe the main reason for high or low VM
> charcoal product depends more on how much oxygen there is in the
> reactor to convert the VM or its building blocks into CO2? Thus
> the more Dr. Antal pressurizes his carbonizer with air prior to
> firing it, the less VM he would have in the charcoal produced in
> his flash reactor??
>
> Gerrit
>
>
>
> On 21-Dec-07, at 1:52 AM, Edward Someus wrote:
>
> SEAN
>
> Technical response on VM:
>
> RE VM has an insecticidal effect
> YES, TARS ARE TOXIC FOR LIFE
> RE Low VM% is obtained at high temperatures, basically
> NOT ONLY, NO MATTER IF YOU HAVE HIGH TEMP AND LONG RESIDENCE TIME
> IF THE TECHNOLOGY HEAT TRANSFER EFFICIENCY IS LOW. == ORGANICS ARE
> LOW HEAT CONDUCTORS.
> RE Higher temperatures produce a more "activated" charcoal too
> ("activated" charcoal has a high adsorption surface area)
> NO, ACTIVATION IS AN DIFFERENT PROCESS, BY HIGHT TEMP ONLY YOU CAN
> NOT REACH HIGH SPECS SURFACE AREA
> RE Now, charring biomass on a forest floor or in the soil will not
> likely allow such high temperatures (~1000C) to be achieved, so one
> wonders how the original Terra Preta soil was made with low temp
> char and does not suffer from toxicity. RE Perhaps any toxicity in
> fresh low temperature charcoal is lost over time once it is in the
> soil.
> TP IS NOT CHAR ONLY, IT IS A BLEND. YES, TOXICITY IS CHANGING BY
> TIME, AND SOONER OR LATER ADAPTED MICROBIOLOGICAL COLONIZATION
> MIGHT OCCUR. BUT THIS PROCESS IS HIGHLY DEPENDING ON SOIL TYPE +
> CLIMATE CONDITIONS AS WELL. TP ORIGINAL WAS IN TROPICAL CLIMATE
> WHERE ORGANIC DEGRADATION IS ALWAYS FAR MORE RAPID THAN IN
> CONTINENTAL CLIMATE. TP MODEN AGE DOES NOT HAVE DECADES OF TIME TO
> WAIT FOR ALL THIS.
>
>
> Sincerely yours: Edward Someus (environmental engineer)
> Terra Humana Clean Tech Ltd. (ISO 9001/ISO 14001)
> 3R Environmental Technologies Ltd.
> ADDRESS: H-1222 Budapest, Szechenyi 59, Hungary
> TEL handy: +(36-20) 201 7557
> TEL / FAX: +(36-1) 424 0224
> TEL SKYPE phone via computer: Edward Someus
> 3R TERRACARBON: http://www.terrenum.net
> 3R CLEANCOAL ENERGY: http://www.nvirocleantech.com
>
> -------Original Message-------
>
> From: Sean K. Barry
> Date: 2007.12.21. 5:43:40
> To: Terrapreta Preta; Gerald Van Koeverden
> Subject: Re: [Terrapreta] volatile matter and char
>
> Hi Gerrit,
>
> What is the source/cause of high volatile matter in char? Does
> this VM (since it is 'volatile') decrease/volatize by itself over a
> short time?
>
> According to the article "VM" content is "a measure of the
> susceptibility of charcoal to further decompose and form carbon
> when heated."
>
> Translation, please??
>
> We've asked Dr. Michael J. Antal this very question, when he was
> subscribed to the list. He was vague about what VM actually is
> then, too. It is measurable as the percent weight (VM%) of a
> charcoal sample (this is done using a "proximate analysis" test),
> but its chemical analysis is a mystery. Some others have recently
> mentioned VM has an insecticidal effect (Dr. Reddy). Edward Someus
> also says high VM% content on charcoal is a problem in soil.
> People working with Eprida, Danny Day, Dr. Christoph Steiner, etc.,
> were wondering if the VM% was a benefit as "food for microbes".
>
> From what I have read about pyrolysis reactions, the VM% content is
> be dictated primarily by maximum internal particle temperature in
> the char bits (this can be somewhat related to residence time in
> the reactor). Low VM% is obtained at high temperatures,
> basically. Higher temperatures produce a more "activated" charcoal
> too ("activated" charcoal has a high adsorption surface area).
> Now, charring biomass on a forest floor or in the soil will not
> likely allow such high temperatures (~1000C) to be achieved, so one
> wonders how the original Terra Preta soil was made with low temp
> char and does not suffer from toxicity. Perhaps any toxicity in
> fresh low temperature charcoal is lost over time once it is in the
> soil.
>
> As you suggest, VM is "volatile", so I imagine it does dissipate
> somewhat off the surface of the charcoal, through reduction by
> oxygen from the air, or water. This has been recognized as a
> "storage" problem for fresh charcoal. Fresh charcoal can
> spontaneously ignite! THis occurs when the VM reacts and creates
> heat). Another question I had was, ... What about charcoal from
> natural forest fires that are quenched out by rain, for instance?.
> Wouldn't these be low temperature and leave toxins in the soil?
> But, as has been observed, soils on which forest fires have run
> across do not stop plant growth. In fact, there is a "bloom" of
> new growth. So, what's up? (with this "toxicity of of high VM% on
> low temperature charcoal" scare).
>
> I think this premise needs testing. I think no none who has
> provided any "field results of using charcoal in soil" here yet,
> has known that the charcoal they used was low VM% or even what
> temperature the char was made at (no data on this presented). I
> can make charcoal with my reactor and control the max temperature
> inside the reactor core. I can do a "proximate analysis" test on
> any charcoal produced and make measurements of VM%. I cannot
> discover any ways yet to characterize the chemical analysis of the
> VM in any way. Dr. Antal got short with me when I asked him about
> doing this. He told me, like in the paper, Volatile Matter is only
> quantifiable, not characterize-able. (Who gets to say, "That's
> bunk!" to a PhD?).
>
> It may be that the processes required to produce low VM% charcoal
> are more expensive than otherwise, so these producers are trying to
> play up the value of their product. I think the premise needs
> testing. I think most testing occurring now is NOT seeing this
> detriment in their plant growth results.
>
> Carry on.
>
> Regards,
>
> SKB
> ----- Original Message -----
> From: Gerald Van Koeverden
> To: Terrapreta Preta
> Sent: Thursday, December 20, 2007 7:53 PM
> Subject: [Terrapreta] volatile matter and char
>
> G.
>
> The article is at the following link:
>
> http://www.ctahr.hawaii.edu/DeenikJ/Downloads/
> Tai_Charcoal_CTAHR_Sym_2007.pdf
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